1. Field of the Invention
The present invention relates generally to transmission of data between computers, and in particular, to a method, apparatus, and article of manufacture for providing access to drawing information and for automated searching, translation, filtering, change notification, version management, and distribution of design drawing data.
2. Description of the Related Art
The use of Computer Aided Design (CAD) application programs is well known in the art. CAD application programs use specific formats to store drawing data. These formats include “.DWG” formatted drawings, “.DWF” formatted drawings, and other formats.
The drawing formats are typically unique to a given CAD application program. The drawing formats were designed to store drawing data on a single computer or a single host computer, and are not easily transported via computer data links, typically because of the size of drawing files and the uniqueness of the computer objects.
However, with the advent of collaborative efforts using computer data links, custom libraries of CAD objects, and other computer-based tools that allow multiple users to access drawings from geographically diverse sites, the drawing formats have become cumbersome to the progress of remote computing. The now widespread use of the Internet, Intranets, and Local Area Networks (LANs) requires that the drawing formats be more compatible with network and web-enabled systems.
Consequently, there is a need in the art for improved techniques to access, translate, and manipulate CAD designed drawing data on a network. Further, there is a need in the art for improved techniques for formatting the data such that the various parties that desire access to the CAD data can obtain the information desired. These problems may be better understood by describing drawing formats and prior art access techniques.
Drawing Formats
As described above, CAD application programs use specific formats to store drawing data. These formats include “.DWG” formatted drawings, “.DWF” formatted drawings, “.DXF” formatted drawings, and other formats.
The “DWG” format is a standard file format for saving vector graphics from within CAD drawing programs such as AutoCAD® available from AutoDesk, Inc.
The “DWF” (drawing web format) format is an industry internet standard recognized by IETF, was developed by the assignee of the present invention, AutoDesk, Inc. and is an open file format for the transfer of drawings over networks, including the internet. DWF is a highly compressed file format that is created from a DWG file. DWF files are easy to publish and view on the web. Further, DWF is a vector graphics format for the transfer of drawings over intranets and the internet. DWF is a graphics format for vector data, unlike GIF or JPEG which are graphics formats for raster data. DWF files can be generated by any application that supports DWF exporting. Further, any DWF file can be viewed by any DWF viewer. DWF uses compression to speed up data transfer times. Further, DWF removes the “non-visual” components of a drawing, like attributes, properties, and complex object behavior. In other words, DWF is an “electronic plot” that is “view-only”. DWF supports hyperlinking, so that vectors or areas in a drawing can be made “active”.
Users of DWF have three benefits: speed, security and precision. DWF provides speed because of the high compression utilized so that files are smaller and faster to transmit and open than full-blown CAD files. Most DWFs are from 50–90 percent smaller than DWG files. DWF provides security because DWF files cannot be modified, so they maintain the integrity of the original CAD DWG file which it is based on. In effect, the DWF is a “digital plot” of the original DWG drawing. DWF provides precision because DWF files are vector-based. When zooming in a DWF, precision is maintained; with other bitmap formats (e.g., GIF or JPEG), zooming results in “fat pixels”.
“DXF” formatted drawings are drawings formatted in the document exchange format. Many CAD systems import and export the DXF format for graphics interchange.
Access Techniques
FIG. 1 illustrates techniques for publishing drawing information (i.e., providing access to drawing information). A drawing program such as AutoCAD® is utilized to create one or more DWG drawings 100. The drawings may then be converted to DWF format 102 (or other format) by the drawing program.
Once the format has been converted by a drawing program user, the DWF file may be published using a web server. For example, in FIG. 1, an information internet server (IIS) 104 (available from Microsoft) is utilized in combination with NT server 106 (available from Microsoft) to publish the DWF information. IIS is an internet file and application server that is included with the Microsoft Windows NT Server operating system. IIS can be used alone as a web server, or in conjunction with compatible technologies to set up internet commerce, to access and manipulate data from a variety of data sources, and to build web applications that take advantage of server script and component code to deliver client-server functionality. Other internet servers that the prior art utilizes include the Netscape Enterprise Server and the Apache server.
Server 104 creates HTML documents 108 that may be viewed by browsers 110. Many browsers are available in the prior art including Internet Explorer and Netscape Navigator. Thus, the prior art provides the ability to view a DWF file 102 and information about the DWF file 102 using a drawing program to convert DWG files to DWF files and a server 104 to create HTML pages 108 for viewing over the internet using a browser 110.